Organizations and networks worldwide have since Friday been dealing with the fallout of massive ransomware attack that exploited a hole in PCs running Microsoft Windows that haven't been updated. The WannaCry hack threatens to delete users' encrypted files in a week if a ransom of $300 isn't met -- doubled if the payment isn't made in within three days.

As companies and individuals take stock Monday morning, the focus is turning to protecting against further attacks.

Experts have these tips to guard against ransomware:

Install Microsoft's official patch. The company rates the update as "critical" for supported Windows releases. If you don't want to install the update for your PC, cybersecurity company Kaspersky Lab has a step-by-step guide to secure computer.

Keep security software up to date.

Beware of unknown emails, especially if there are attachments or links. Do not enable macros, cybersecurity company Symantec says.

Backing up data, Symantec adds, "is the single most effect way of combating ransomware infection."

Apple is not invulnerable to ransomware attacks, "a common misconception," one expert tells CNBC. The same goes for cloud services, though they can be helpful.

Tempting as it may be in order to resolve your crisis quickly, law enforcement and cybersecurity experts don't recommend paying the ransom. It gives incentives to hackers and pays for future attacks.

"My answer is, never pay the ransom," Lawrence Abrams, a New York-based blogger who runs BleepingComputer.com told The Associated Press. "But at the same time, I also know that if you're someone who's been affected and you've lost all your children's photographs or you've lost all your data or you lost your thesis, sometimes $300 is worth it, you know?"